Epidemiology and Clinical Study of Nystagmus

Abstract: Introduction: Nystagmus is a repetitive to and fro movement of the eyes and can affect vision and involve individuals of all ages. Previous research into the pathophysiology of this disease has been based on case series or small numbers of patients. Improvements in and standardisation of electrodiagnostics and eye movement recordings have enabled scientists to diagnose and characterise the different nystagmus types more accurately. Purpose: The research into nystagmus carried out at the University of Leicester had several aims. The first population-based study on the prevalence of nystagmus was carried out within the county of Leicestershire. The second study was aimed at examining the clinical features of patients with different types of infantile and neurological nystagmus in order to characterise any specific features associated with this groups of patients. The final study was carried out with the aim of investigating the distribution of refractive errors in patients with nystagmus and to determine if the process of emmetropization in ocular development is influenced by the presence of nystagmus. Methods: Ethical approval was obtained. Patients were recruited for the epidemiological study from both the community and hospitals within Leicestershire. Patients for the clinical and refractive error studies were additionally recruited from outside the county. A further 602 normal subjects volunteered to participate in the refraction study. Results: The epidemiological study estimates the prevalence of nystagmus to be 16.6 per 10 000 (under 18 population) and 26.5 per 10 000 (over 18 population). The clinical study showed differences in visual acuity, stereopsis, anomalous head posture and conjugacy of nystagmus amongst different clinical groups. Finally, the refractive errors study suggests that the process of emmetropization is influenced by the presence of nystagmus. Conclusion: These studies provide previously unknown data about nystagmus and provide a platform for further research into this condition.